Visible-Light Photocatalytic Conversion of Carbon Dioxide by Ni(II) Complexes with N4S2 Coordination: Highly Efficient and Selective Production of Formate

Abstract

Summary

A photochemical reduction of CO₂ to formate was shown using the nickel complexes Ni(pbi)(pyS)2 or Ni(pbt)(pyS)2 as catalysts in combination with the organic photosensitizer Eosin Y. Turnover numbers (TONs) of up to 14000 and a selectivity of >99% for formate were reached in ethanol/water. The experiments were conducted under visible-light irradiation (λ > 400 nm) using TEOA as sacrificial electron donor (see section SEDs below).

Advances and special progress

A set of novel nickel complexes have been developed and shown to possess remarkably high efficiencies as catalysts in CO₂ reduction.

Additional remarks

The nickel complexes were active catalysts for hydrogen photoreduction under argon atmosphere.

Content of the published article in detail

The article contains results for the reduction of CO₂ to formate under visible-light catalysis using nickel complexes and an organic photosensitizer. The catalytic system performs best (referring to the TON of formate production) in ethanol/water with complex Ni(pbi)(pyS)2 as a catalyst.

Catalyst

Ni(pbi)(pyS)2 Ni(pbt)(pyS)2

Photosensitizer

Eosin Y

Investigation

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	.	.	.	.	TON HCOOH	.	.	.
1.	Ni(pbi)(pyS)2	0.004	Eosin Y	2	TEOA	0.4	H2O					14000
2.	Ni(pbt)(pyS)2	0.004	Eosin Y	2	TEOA	0.4	H2O					13100

Investigation-Name: Table 1Export

Sacrificial Electron Donor

In this study, the experiments were done with the sacrificial electron donor TEOA (triethanolamine).

Additives

In this study, different additives were used.